Engine device for reducing unburned hydrocarbons



April 1.962 M. E. BALE, JR, ET AL 3,027,884

ENGINE DEVICE FOR REDUCING UNBURNED HYDROCARBONS Filed Nov. 18, 1960 7%Jaw/2 ATTORNEY United States 3,027,884 ENGINE DEVICE FOR REDUCINGUNBURNED HYDRQCARIl-ONS Maurice E. Bale, In, and Donald G. Guetersloh,Anderson, Ind, assignors to General Motors orporation, De-

troit, Mich, a corporation of Delaware Filed Nov. 18, 1960, Ser. No.76,288 5 Claims. (Cl. 123-27) The present invention relates to a chargeforming device for an internal combustion engine constructed so as toconsiderably reduce the emission of unburned hydrocarbons from theengine. More specifically, the present invention relates to a mechanismwhich is designed to reduce unburned hydrocarbons during vehiclecoasting operation.

It is well known in the automotive fuel systems art that during vehiclecoasting conditions fuel continues to be drawn through the carburetoreven though the throttle is closed and as a consequence unburnedhydrocarbons are discharged through the vehicle exhaust system resultingin a contamination of the atmosphere. In the past, various types ofmechanisms have been developed to overcome this emission of unburnedfuels. The most common approach has been to provide means for positivelycutting off the flow of fuel during coasting operation.

In general, coasting fuel shut-off devices have not proved to becommercially acceptable for several reasons, one of which has been thecost and complication of such devices. In addition, however, cutting offthe flow of fuel during coasting operation has had a very definiteoperating disadvantage in that the carburetor fuel supply lines as wellas the intake manifold are dried out during coasting operation. As aconsequence, when the operator again desires to resume normal drivingoperation the engine has frequently stalled for want of fuel and adefinite jerk or bump is felt in restarting of the engine.

In the present invention, when the vehicle is coasting, means isprovided for slightly opening the throttle whereby sufficient air isadmitted to the engine to maintain a combustible mixture in thecombustion chamber, even in the presence of the high exhaust dilutionwhich occurs under coasting conditions. In this way the fuel iscompeltely combusted leaving the exhaust relatively free of unburnedhydrocarbons. At the same time, means is provided for retarding theengines spark so that the fuel-air mixture being burned during coastingdoes not contribute to the engine power output.

More specifically, the present invention includes a manifold vacuumresponsive mechanism operatively connected to both the throttle and theengine spark distributor in such a way that under normal engineoperating conditions the throttle is controlled by the operator and thedistributor is controlled in its normal manner. However, underconditions of abnormally high manifold vacuum, as would occur duringengine vehicle coasting conditions, the manifold vacuum responsivemechanism will be actuated to move the throttle to a slightly openedposition and also to rotate the distributor to retard the spark.

The details as well as other objects and advantages of the presentinvention will be apparent from a perusal of the detailed descriptionwhich follows:

In the drawings:

FIGURE 1 is a diagrammatic representation of the invention embodied onan engine; and

FIGURE 2 is an enlarged sectional View of the vacuum switch.

Referring to FIGURE 1, an engine intake manifold is indicated generallyat on which a carburetor 12 is ice mounted to supply a combustiblecharge thereto. Carburetor 12 includes a throttle valve 14 rotatablydisposed in induction passage 16 for controlling the quantity ofcombustible charge supplied to the intake manifold. A lever 18 is fixedto throttle shaft 20 and includes an extended portion 22 adapted to beengaged by one end 24 of a bellcrank lever 26 pivotally mounted on thecarburetor casing.

A first servo device, indicated generally at 28, is mounted on thecarburetor casing through a suitable bracket 30. The servo includes apair of easing members 32 and 34 which coact to peripherally clamp aflexible diaphragm 36 therebetween. A rod 38 is centrally secured todiaphragm 36 while the other end of the rod is suitably articulated tolever 26. A spring element 40 is disposed between casing 32 anddiaphragm 36 and under normal operating conditions urges lever 26,through diaphragm 36 and rod 38, to a position not atfecting theoperation of throttle 14.

An electrical spark distributor is indicated at 42. Distributor 42 is ofconventional design and includes a ter minal housing 44 within which abreaker plate 45 is disposed for rotative adjustment relative to thehousing to vary spark advance. Rotation of the breaker plate iscontrolled in the conventional manner by a servo device 46 articulatedthereto through a link 47 and which device communicates through aconduit 48 with manifold 10. In the normal manner, variations inmanifold vacuum will be transmitted to servo 'device 46 which will inturn vary the spark advance. The spark will be retarded under conditionsof low manifold vacuum and advanced under conditions of high vacuum.

The distributor rotor, not shown, is adapted to be driven by a camshaftdriven shaft 50 which extends through a base member 52 into housing 44.Housing or cap 44 is clamped to base 52 the latter which also supportsbreaker plate 45.

A bracket or collar 59 is mounted on the engine block or other enginesupporting part and supports servo device 54 to permit rotation of base52.

An additional servo device 54 is connected through a link 56 and a lever58 fixed to base 52 to permit the base to be adjusted to vary sparkadvance independently of breaker plate controlling servo device 46.

The actuation of servo devices 28 and 54 is controlled by vacuum switchdevice 60. Switch 60 communicates through conduit 62 with manifoldvacuum conduit 48 and, in turn, with servo devices 28 and 54 throughconduits 64 and 66. Referring to FIGURE 2, switch 60 includes a body 68within the bore 70 of which a valve member 72 is slidably disposed. Oneend of valve member 72 is centrally secured to a flexible diaphragm 74peripherally clamped between casings 76 and 78. Casing 78 is suitablysecured to valve body 68. An overcenter spring 88 is mounted within acasing 82 fixed to casing 76. Casing 82 is centrally apertured to permita stud portion 84 to extend therethrough and be secured to spring 80.

Conduits 62 and 64 respectively communicate with bore 70 and radial port86 in valve body 68. Valve member 72 includes an axial passage 90 havingspaced radial ports 92 and 94. An annular groove 96 is formed in member72. Radial port 92 continuously admits manifold vacuum to chamber 98formed by diaphragm 74, casing 78 and enlarged portion 100 of valve body68. Under normal engine operating conditions, spring 162 will biasdiaphragm 74 and valve member 72 to the pdsition shown in FIGURE 2against the force of manifold vacuum acting on the diaphragm. In thisposition, annular groove 96 registers with port 86 venting servo de- 3vices 28 and 54 to atmosphere through port 194 in body 68.

Under vehicle coasting conditions, however, manifold vacuum willincrease sufiiciently in chamber 98 to move diaphragm 74 and valvemember 72 to the right against the force of spring 102. In this latterposition, radial port 94 in valve member 72 registers with port 86admitting manifold vacuum to conduit 64. Under these conditions, servo28 moves throttle 14 to a slightly open position while servo 54 retardsthe distributor advance whereby any fuel drawn through carburetor 12during coasting will be consumed without adding appreciably to the poweroutput of the engine.

Overcenter spring 80 insures that valve member 72 Will not hunt betweenthe two positions in which port 86 is either communicated with theatmosphere or manifold vacuum.

We claim:

1. An internal combustion engine comprising an inlet manifold, acarburetor mounted on said manifold and adapted to supply a combustiblemixture thereto, said carburetor including a rotatable throttle valveadapted to control the quantity of combustible mixture supplied to saidmanifold, a first servo device adapted to engage said throttle valvewhen said valve is in a closed position to move said valve to apartially open position, a spark distributor mechanism, a second servodevice adapted to vary the spark advance of said spark distributormechanism, a vacuum switch mechanism normally venting said first andsecond servo devices to atmosphere, a third servo device connected tosaid vacuum switch mechanism, conduit means communicating said thirdservo device with said inlet manifold whereby when manifold vacuumexceeds a predetermined value said third servo device will move saidvacuum switch mechanism to admit manifold vacuum to said first andsecond servo devices causing said first servo device to partially opensaid throttle valve and said second servo device to retard said sparkdistributor mechanism spark advance.

.2. An internal combution engine comprising an inlet manifold, acarburetor mounted on said manifold and adapted to supply a combustiblemixture thereto, said carburetor including a rotatable throttle valveadapted to control the quantity of combustible mixture supplied to saidmanifold, a first servo device adapted to engage said throttle valvewhen said valve is in a closed position to move said valve to apartially open position, a lost motion connection between said firstservo device and said throttle valve permitting said valve to be openedirrespective of the operation of said device, a spark distributormechanism, a second servo device adapted to vary the spark advance ofsaid distributor mechanism, a vacuum switch mechanism normally ventingsaid first and second servo devices to atmosphere, a third servo deviceconnected to said vacuum switch mechanism, conduit means communicatingsaid third selvo device with said inlet manifold whereby when manifoldvacuum exceeds a predetermined value said third servo device will movesaid vacuum switch mechanism to admit manifold vacuum to said first andsecond servo devices causing said first servo device to partially opensaid throttle valve and said second servo device to retard saiddistributor mechanism spark advance.

3. An internal combustion engine comprising an inlet manifold, acarburetor mounted on said manifold and adapted to supply a combustiblemixture thereto, said carburetor including a throttle valve adapted tocontrol the quantity of mixture supplied to said manifold, a first servodevice adapted to operatively engage the throttle valve when said valveis in a closed position and to move said valve to a partially openposition, an electrical spark distributor including a base, a terminalhousing mounted on said base, and a breaker plate mounted on said baseand rotatable relative thereto, a second servo device connected to saidbreaker plate and adapted to rotate said plate relative to said housing,first conduit means communicating said second servo device with saidinlet manifold whereby manifold vacuum is adapted to act on said seconddevice, a third servo device connected to said distributor base andadapted to adjustably rotate the same, and a vacuum switch including anadjustable valve member, a diaphragm connected to said member, secondconduit means communicating said vacuum switch with said first and thirdservo devices, spring means normally biasing said valve member to aposition communicating said second conduit means to atmosphere to rendersaid first and third servo devices inoperative, additional conduit meanscommunicating said vacuum switch diaphragm with said inlet manifold,manifold vacuum acting on said diaphragm being adapted to overcome saidspring under certain operating conditions and move said valve member toa position communicating said additional conduit means with said secondconduit means to render said first and third servo devices operativerespectively to move said throttle valve to a partially open positionand to retard the distributor spark.

4. An internal combustion engine as set forth in claim 3 in which a lostmotion connection is provided between said first servo device and saidthrottle valve permitting said valve to be opened irrespective of theoperation of said device.

5. An internal combustion engine as set forth in claim 1 which includesa fourth servo device operatively connected to the spark distributormechanism to vary the spark advance thereof, and conduit meanscontinuously communicating said fourth device with the inlet manifold.

References Cited in the file of this patent UNITED STATES PATENTS1,969,682 Arthur Aug. 7, 1934 2,129,608 Vanderpoel Sept. 6, 19382,229,851 Hutford Jan. 28, 1941 2,466,090 Fageol Apr. 5, 1949 2,532,069Mallory Nov. 28, 1950 2,672,855 Thomas Mar. 23, 1954

3. AN INTERNAL COMBUSTION ENGINE COMPRISING AN INLET MANIFOLD, ACARBURETOR MOUNTED ON SAID MANIFOLD AND ADAPTED TO SUPPLY A COMBUSTIBLEMIXTURE THERETO, SAID CARBURETOR INCLUDING A THROTTLE VALUE ADAPTED TOCONTROL THE QUANTITY OF MIXTURE SUPPLIED TO SAID MANIFOLD, A FIRST SERVODEVICE ADAPTED TO OPERATIVELY ENGAGE THE THROTTLE VALVE WHEN SAID VALVEIS IN A CLOSED POSITION AND TO MOVE SAID VALVE TO A PARTIALLY OPENPOSITION, AN ELECTRICAL SPARK DISTRIBUTOR INCLUDING A BASE, A TERMINALHOUSING MOUNTED ON SAID BASE, AND A BREAKER PLATE MOUNTED ON SAID BASEAND ROTATABLE RELATIVE THERETO, A SECOND SERVO DEVICE CONNECTED TO SAIDBREAKER PLATE AND ADAPTED TO ROTATE SAID PLATE RELATIVE TO SAID HOUSING,FIRST CONDUIT MEANS COMMUNICATING SAID SECOND SERVO DEVICE WITH SAIDINLET MANIFOLD WHEREBY MANIFOLD VACUUM IS ADAPTED TO ACT ON SAID SECONDDEVICE, A THIRD SERVO DEVICE CONNECTED TO SAID DISTRIBUTOR BASE ANDADAPTED TO ADJUSTABLY ROTATE THE SAME, AND A VACUUM SWITCH INCLUDING ANADJUSTABLE VALVE MEMBER, A DIAPHRAGM CONNECTED TO SAID MEMBER, SECONDCONDUIT MEANS COMMUNICATING SAID VACUUM SWITCH WITH SAID FIRST AND THIRDSERVO DEVICES, SPRING MEANS NORMALLY BIASING SAID VALVE MEMBER TO SPOSITION COMMUNICATING SAID SECOND CONDUIT MEANS TO ATMOSPHERE TO RENDERSAID FIRST AND THIRD SERCO DEVICES INOPERATIVE, ADDITIONAL CONDUIT MEANSCOMMUNICATING SAID VACUUM SWITCH DIAPHRAGM WITH SAID INLET MANIFOLD,MANIFOLD VACUUM ACTING ON SAID DIAPHRAGM BEING ADAPTED TO OVERCOME SAIDSPRING UNDER CERTAIN OPERATING CONDITIONS AND MOVE SAID VALVE MEMBER TOA POSITION COMMUNICATING SAID ADDITIONAL CONDUIT MEANS WITH SAID SECONDCONDUIT MEANS TO RENDER SAID FIRST AND THIRD SERVO DEVICES OPERATIVERESPECTIVELY TO MOVE SAID THROTTLE VALVE TO A PARTIALLY OPEN POSITIONAND TO RETARD THE DISTRIBUTOR SPARK.